1. Field of the Invention
The present invention relates to an image forming system such as a scanner, a facsimile machine or the like, and, more particularly, it relates to an original feeding and reading apparatus in which an image recorded on an original is read while feeding the original.
2. Related Background Art
In the past, original feeding and reading apparatuses which read an image recorded on an original are already known, as disclosed in U.S. Pat. Nos. 4,446,364 and 4,805,032, and Japanese Patent Laid-Open No. 58-127463. An example of such apparatus will be explained with reference to FIG. 12.
The apparatus comprises a pick-up roller 61 for shifting a plurality of originals M stacked in an original tray 64 downstream, a feed roller 62 for feeding the shifted original M downstream one by one, and a separating pad 63 for separating the original M to be fed from the other originals. These elements 61-63 are disposed in the vicinity of an outlet of the original tray 64. Downstream of these elements, an image sensor 65 the contact type and a conveying roller 66 pressed against the image sensor 65 for feeding the original are arranged. Elements 65, 66 read an image recorded on the original while pinching and feeding the original. Further, an original detecting sensor 67 is arranged at an upstream side of the image sensor 65, and the conveying roller 66 is driven in response to a detection signal from the detecting sensor 67, while the image sensor 65 reads the image information on the original. After the reading operation has been finished, the original M is ejected onto an ejector tray 68.
However, in the above-mentioned conventional original feeding and reading apparatus, since the original M is pinched and fed by the urging contact between the image sensor 65 the contact type and the conveying roller 66, the conveying roller 66 continues to frictionally drive the original M so long as the original M is pinched and fed by these elements 65, 66, with the result that there arise problems that the roller 66 and a guide member 65a of the image sensor 65 wear away and that a driving source of the roller 66 is subjected to a large load. In order to alleviate these problems, there has been proposed a technique in which the wear of the conveying roller 66 and the load of the driving source are reduced by using a guide member 65a made of low friction material with respect to the conveying roller 66, but this technique resulted in a considerable increase in the cost of the apparatus.
Further, an apparatus wherein conveying means are arranged at upstream and downstream sides of the image sensor 65 the contact type and a means for lightly contacting the original M against the image sensor 65 to reduce the load has also been proposed However, this apparatus was large-sized and expensive.